# Copyright 2019 MongoDB Inc. # # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. # You may obtain a copy of the License at # # http://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. """Generate build.ninja files from SCons aliases.""" import sys import os import importlib import io import shutil import shlex from glob import glob from os.path import join as joinpath from os.path import splitext import SCons from SCons.Action import _string_from_cmd_list, get_default_ENV from SCons.Util import is_List, flatten_sequence from SCons.Script import COMMAND_LINE_TARGETS NINJA_STATE = None NINJA_SYNTAX = "NINJA_SYNTAX" NINJA_RULES = "__NINJA_CUSTOM_RULES" NINJA_POOLS = "__NINJA_CUSTOM_POOLS" NINJA_CUSTOM_HANDLERS = "__NINJA_CUSTOM_HANDLERS" NINJA_BUILD = "NINJA_BUILD" NINJA_WHEREIS_MEMO = {} NINJA_STAT_MEMO = {} __NINJA_RULE_MAPPING = {} # These are the types that get_command can do something with COMMAND_TYPES = ( SCons.Action.CommandAction, SCons.Action.CommandGeneratorAction, ) def _install_action_function(_env, node): """Install files using the install or copy commands""" return { "outputs": get_outputs(node), "rule": "INSTALL", "inputs": [get_path(src_file(s)) for s in node.sources], "implicit": get_dependencies(node), } def _mkdir_action_function(env, node): return { "outputs": get_outputs(node), "rule": "CMD", # implicit explicitly omitted, we translate these so they can be # used by anything that depends on these but commonly this is # hit with a node that will depend on all of the fake # srcnode's that SCons will never give us a rule for leading # to an invalid ninja file. "variables": { # On Windows mkdir "-p" is always on "cmd": "{mkdir} $out".format( mkdir="mkdir" if env["PLATFORM"] == "win32" else "mkdir -p", ), }, } def _lib_symlink_action_function(_env, node): """Create shared object symlinks if any need to be created""" symlinks = getattr(getattr(node, "attributes", None), "shliblinks", None) if not symlinks or symlinks is None: return None outputs = [link.get_dir().rel_path(linktgt) for link, linktgt in symlinks] inputs = [link.get_path() for link, _ in symlinks] return { "outputs": outputs, "inputs": inputs, "rule": "SYMLINK", "implicit": get_dependencies(node), } def is_valid_dependent_node(node): """ Return True if node is not an alias or is an alias that has children This prevents us from making phony targets that depend on other phony targets that will never have an associated ninja build target. We also have to specify that it's an alias when doing the builder check because some nodes (like src files) won't have builders but are valid implicit dependencies. """ if isinstance(node, SCons.Node.Alias.Alias): return node.children() if not node.env: return True return not node.env.get("NINJA_SKIP") def alias_to_ninja_build(node): """Convert an Alias node into a Ninja phony target""" return { "outputs": get_outputs(node), "rule": "phony", "implicit": [ get_path(src_file(n)) for n in node.children() if is_valid_dependent_node(n) ], } def get_order_only(node): """Return a list of order only dependencies for node.""" if node.prerequisites is None: return [] return [get_path(src_file(prereq)) for prereq in node.prerequisites] def get_dependencies(node, skip_sources=False): """Return a list of dependencies for node.""" if skip_sources: return [ get_path(src_file(child)) for child in node.children() if child not in node.sources ] return [get_path(src_file(child)) for child in node.children()] def get_inputs(node): """Collect the Ninja inputs for node.""" executor = node.get_executor() if executor is not None: inputs = executor.get_all_sources() else: inputs = node.sources inputs = [get_path(src_file(o)) for o in inputs] return inputs def get_outputs(node): """Collect the Ninja outputs for node.""" executor = node.get_executor() if executor is not None: outputs = executor.get_all_targets() else: if hasattr(node, "target_peers"): outputs = node.target_peers else: outputs = [node] outputs = [get_path(o) for o in outputs] return outputs class SConsToNinjaTranslator: """Translates SCons Actions into Ninja build objects.""" def __init__(self, env): self.env = env self.func_handlers = { # Skip conftest builders "_createSource": ninja_noop, # SCons has a custom FunctionAction that just makes sure the # target isn't static. We let the commands that ninja runs do # this check for us. "SharedFlagChecker": ninja_noop, # The install builder is implemented as a function action. "installFunc": _install_action_function, "MkdirFunc": _mkdir_action_function, "LibSymlinksActionFunction": _lib_symlink_action_function, } self.loaded_custom = False # pylint: disable=too-many-return-statements def action_to_ninja_build(self, node, action=None): """Generate build arguments dictionary for node.""" if not self.loaded_custom: self.func_handlers.update(self.env[NINJA_CUSTOM_HANDLERS]) self.loaded_custom = True if node.builder is None: return None if action is None: action = node.builder.action if node.env and node.env.get("NINJA_SKIP"): return None build = {} # Ideally this should never happen, and we do try to filter # Ninja builders out of being sources of ninja builders but I # can't fix every DAG problem so we just skip ninja_builders # if we find one if node.builder == self.env["BUILDERS"]["Ninja"]: build = None elif isinstance(action, SCons.Action.FunctionAction): build = self.handle_func_action(node, action) elif isinstance(action, SCons.Action.LazyAction): # pylint: disable=protected-access action = action._generate_cache(node.env if node.env else self.env) build = self.action_to_ninja_build(node, action=action) elif isinstance(action, SCons.Action.ListAction): build = self.handle_list_action(node, action) elif isinstance(action, COMMAND_TYPES): build = get_command(node.env if node.env else self.env, node, action) else: raise Exception("Got an unbuildable ListAction for: {}".format(str(node))) if build is not None: build["order_only"] = get_order_only(node) return build def handle_func_action(self, node, action): """Determine how to handle the function action.""" name = action.function_name() # This is the name given by the Subst/Textfile builders. So return the # node to indicate that SCons is required. We skip sources here because # dependencies don't really matter when we're going to shove these to # the bottom of ninja's DAG anyway and Textfile builders can have text # content as their source which doesn't work as an implicit dep in # ninja. if name == "_action": return { "rule": "TEMPLATE", "outputs": get_outputs(node), "implicit": get_dependencies(node, skip_sources=True), } handler = self.func_handlers.get(name, None) if handler is not None: return handler(node.env if node.env else self.env, node) raise Exception( "Found unhandled function action {}, " " generating scons command to build\n" "Note: this is less efficient than Ninja," " you can write your own ninja build generator for" " this function using NinjaRegisterFunctionHandler".format(name) ) # pylint: disable=too-many-branches def handle_list_action(self, node, action): """TODO write this comment""" results = [ self.action_to_ninja_build(node, action=act) for act in action.list if act is not None ] results = [ result for result in results if result is not None and result["outputs"] ] if not results: return None # No need to process the results if we only got a single result if len(results) == 1: return results[0] all_outputs = list({output for build in results for output in build["outputs"]}) dependencies = list({dep for build in results for dep in build["implicit"]}) if results[0]["rule"] == "CMD": cmdline = "" for cmd in results: # Occasionally a command line will expand to a # whitespace only string (i.e. ' '). Which is not a # valid command but does not trigger the empty command # condition if not cmdstr. So here we strip preceding # and proceeding whitespace to make strings like the # above become empty strings and so will be skipped. cmdstr = cmd["variables"]["cmd"].strip() if not cmdstr: continue # Skip duplicate commands if cmdstr in cmdline: continue if cmdline: cmdline += " && " cmdline += cmdstr # Remove all preceding and proceeding whitespace cmdline = cmdline.strip() # Make sure we didn't generate an empty cmdline if cmdline: ninja_build = { "outputs": all_outputs, "rule": "CMD", "variables": { "cmd": cmdline, "env": get_command_env(node.env if node.env else self.env), }, "implicit": dependencies, } if node.env and node.env.get("NINJA_POOL", None) is not None: ninja_build["pool"] = node.env["pool"] return ninja_build elif results[0]["rule"] == "phony": return { "outputs": all_outputs, "rule": "phony", "implicit": dependencies, } elif results[0]["rule"] == "INSTALL": return { "outputs": all_outputs, "rule": "INSTALL", "inputs": [get_path(src_file(s)) for s in node.sources], "implicit": dependencies, } raise Exception("Unhandled list action with rule: " + results[0]["rule"]) # pylint: disable=too-many-instance-attributes class NinjaState: """Maintains state of Ninja build system as it's translated from SCons.""" def __init__(self, env, writer_class): self.env = env self.writer_class = writer_class self.__generated = False self.translator = SConsToNinjaTranslator(env) self.generated_suffixes = env.get("NINJA_GENERATED_SOURCE_SUFFIXES", []) # List of generated builds that will be written at a later stage self.builds = list() # List of targets for which we have generated a build. This # allows us to take multiple Alias nodes as sources and to not # fail to build if they have overlapping targets. self.built = set() # SCons sets this variable to a function which knows how to do # shell quoting on whatever platform it's run on. Here we use it # to make the SCONS_INVOCATION variable properly quoted for things # like CCFLAGS escape = env.get("ESCAPE", lambda x: x) self.variables = { "COPY": "cmd.exe /c 1>NUL copy" if sys.platform == "win32" else "cp", "SCONS_INVOCATION": "{} {} __NINJA_NO=1 $out".format( sys.executable, " ".join( [escape(arg) for arg in sys.argv if arg not in COMMAND_LINE_TARGETS] ), ), "SCONS_INVOCATION_W_TARGETS": "{} {}".format( sys.executable, " ".join([escape(arg) for arg in sys.argv]) ), # This must be set to a global default per: # https://ninja-build.org/manual.html # # (The deps section) "msvc_deps_prefix": "Note: including file:", } self.rules = { "CMD": { "command": "cmd /c $env$cmd" if sys.platform == "win32" else "$env$cmd", "description": "Building $out", "pool": "local_pool", }, # We add the deps processing variables to this below. We # don't pipe these through cmd.exe on Windows because we # use this to generate a compile_commands.json database # which can't use the shell command as it's compile # command. "CC": { "command": "$env$CC @$out.rsp", "description": "Compiling $out", "rspfile": "$out.rsp", "rspfile_content": "$rspc", }, "CXX": { "command": "$env$CXX @$out.rsp", "description": "Compiling $out", "rspfile": "$out.rsp", "rspfile_content": "$rspc", }, "LINK": { "command": "$env$LINK @$out.rsp", "description": "Linking $out", "rspfile": "$out.rsp", "rspfile_content": "$rspc", "pool": "local_pool", }, "AR": { "command": "$env$AR @$out.rsp", "description": "Archiving $out", "rspfile": "$out.rsp", "rspfile_content": "$rspc", "pool": "local_pool", }, "SYMLINK": { "command": ( "cmd /c mklink $out $in" if sys.platform == "win32" else "ln -s $in $out" ), "description": "Symlink $in -> $out", }, "INSTALL": { "command": "$COPY $in $out", "description": "Install $out", "pool": "install_pool", # On Windows cmd.exe /c copy does not always correctly # update the timestamp on the output file. This leads # to a stuck constant timestamp in the Ninja database # and needless rebuilds. # # Adding restat here ensures that Ninja always checks # the copy updated the timestamp and that Ninja has # the correct information. "restat": 1, }, "TEMPLATE": { "command": "$SCONS_INVOCATION $out", "description": "Rendering $out", "pool": "scons_pool", "restat": 1, }, "SCONS": { "command": "$SCONS_INVOCATION $out", "description": "SCons $out", "pool": "scons_pool", # restat # if present, causes Ninja to re-stat the command's outputs # after execution of the command. Each output whose # modification time the command did not change will be # treated as though it had never needed to be built. This # may cause the output's reverse dependencies to be removed # from the list of pending build actions. # # We use restat any time we execute SCons because # SCons calls in Ninja typically create multiple # targets. But since SCons is doing it's own up to # date-ness checks it may only update say one of # them. Restat will find out which of the multiple # build targets did actually change then only rebuild # those targets which depend specifically on that # output. "restat": 1, }, "REGENERATE": { "command": "$SCONS_INVOCATION_W_TARGETS", "description": "Regenerating $out", "generator": 1, # Console pool restricts to 1 job running at a time, # it additionally has some special handling about # passing stdin, stdout, etc to process in this pool # that we need for SCons to behave correctly when # regenerating Ninja "pool": "console", # Again we restat in case Ninja thought the # build.ninja should be regenerated but SCons knew # better. "restat": 1, }, } self.pools = { "local_pool": self.env.GetOption("num_jobs"), "install_pool": self.env.GetOption("num_jobs") / 2, "scons_pool": 1, } for rule in ["CC", "CXX"]: if env["PLATFORM"] == "win32": self.rules[rule]["deps"] = "msvc" else: self.rules[rule]["deps"] = "gcc" self.rules[rule]["depfile"] = "$out.d" def add_build(self, node): if not node.has_builder(): return False if isinstance(node, SCons.Node.Alias.Alias): build = alias_to_ninja_build(node) else: build = self.translator.action_to_ninja_build(node) # Some things are unbuild-able or need not be built in Ninja if build is None: return False self.builds.append(build) self.built.update(build["outputs"]) return True def is_generated_source(self, output): """Check if output ends with a known generated suffix.""" _, suffix = splitext(output) return suffix in self.generated_suffixes def has_generated_sources(self, output): """ Determine if output indicates this is a generated header file. """ for generated in output: if self.is_generated_source(generated): return True return False # pylint: disable=too-many-branches,too-many-locals def generate(self, ninja_file): """ Generate the build.ninja. This should only be called once for the lifetime of this object. """ if self.__generated: return self.rules.update(self.env.get(NINJA_RULES, {})) self.pools.update(self.env.get(NINJA_POOLS, {})) content = io.StringIO() ninja = self.writer_class(content, width=100) ninja.comment("Generated by scons. DO NOT EDIT.") for pool_name, size in self.pools.items(): ninja.pool(pool_name, size) for var, val in self.variables.items(): ninja.variable(var, val) for rule, kwargs in self.rules.items(): ninja.rule(rule, **kwargs) generated_source_files = { output # First find builds which have header files in their outputs. for build in self.builds if self.has_generated_sources(build["outputs"]) for output in build["outputs"] # Collect only the header files from the builds with them # in their output. We do this because is_generated_source # returns True if it finds a header in any of the outputs, # here we need to filter so we only have the headers and # not the other outputs. if self.is_generated_source(output) } if generated_source_files: ninja.build( outputs="_generated_sources", rule="phony", implicit=list(generated_source_files), ) template_builders = [] for build in self.builds: if build["rule"] == "TEMPLATE": template_builders.append(build) continue implicit = build.get("implicit", []) implicit.append(ninja_file) build["implicit"] = implicit # Don't make generated sources depend on each other. We # have to check that none of the outputs are generated # sources and none of the direct implicit dependencies are # generated sources or else we will create a dependency # cycle. if ( generated_source_files and not build["rule"] == "INSTALL" and set(build["outputs"]).isdisjoint(generated_source_files) and set(implicit).isdisjoint(generated_source_files) ): # Make all non-generated source targets depend on # _generated_sources. We use order_only for generated # sources so that we don't rebuild the world if one # generated source was rebuilt. We just need to make # sure that all of these sources are generated before # other builds. order_only = build.get("order_only", []) order_only.append("_generated_sources") build["order_only"] = order_only # When using a depfile Ninja can only have a single output # but SCons will usually have emitted an output for every # thing a command will create because it's caching is much # more complex than Ninja's. This includes things like DWO # files. Here we make sure that Ninja only ever sees one # target when using a depfile. It will still have a command # that will create all of the outputs but most targets don't # depend direclty on DWO files and so this assumption is safe # to make. rule = self.rules.get(build["rule"]) # Some rules like 'phony' and other builtins we don't have # listed in self.rules so verify that we got a result # before trying to check if it has a deps key. # # Anything using deps or rspfile in Ninja can only have a single # output, but we may have a build which actually produces # multiple outputs which other targets can depend on. Here we # slice up the outputs so we have a single output which we will # use for the "real" builder and multiple phony targets that # match the file names of the remaining outputs. This way any # build can depend on any output from any build. if rule is not None and (rule.get("deps") or rule.get("rspfile")): first_output, remaining_outputs = ( build["outputs"][0], build["outputs"][1:], ) if remaining_outputs: ninja.build( outputs=remaining_outputs, rule="phony", implicit=first_output, ) build["outputs"] = first_output ninja.build(**build) template_builds = dict() for template_builder in template_builders: # Special handling for outputs and implicit since we need to # aggregate not replace for each builder. for agg_key in ["outputs", "implicit"]: new_val = template_builds.get(agg_key, []) # Use pop so the key is removed and so the update # below will not overwrite our aggregated values. cur_val = template_builder.pop(agg_key, []) if isinstance(cur_val, list): new_val += cur_val else: new_val.append(cur_val) template_builds[agg_key] = new_val # Collect all other keys template_builds.update(template_builder) if template_builds.get("outputs", []): ninja.build(**template_builds) # We have to glob the SCons files here to teach the ninja file # how to regenerate itself. We'll never see ourselves in the # DAG walk so we can't rely on action_to_ninja_build to # generate this rule even though SCons should know we're # dependent on SCons files. # # TODO: We're working on getting an API into SCons that will # allow us to query the actual SConscripts used. Right now # this glob method has deficiencies like skipping # jstests/SConscript and being specific to the MongoDB # repository layout. ninja.build( ninja_file, rule="REGENERATE", implicit=[ self.env.File("#SConstruct").get_abspath(), os.path.abspath(__file__), ] + glob("src/**/SConscript", recursive=True), ) # If we ever change the name/s of the rules that include # compile commands (i.e. something like CC) we will need to # update this build to reflect that complete list. ninja.build( "compile_commands.json", rule="CMD", pool="console", variables={ "cmd": "ninja -f {} -t compdb CC CXX > compile_commands.json".format( ninja_file ) }, ) ninja.build( "compiledb", rule="phony", implicit=["compile_commands.json"], ) # Look in SCons's list of DEFAULT_TARGETS, find the ones that # we generated a ninja build rule for. scons_default_targets = [ get_path(tgt) for tgt in SCons.Script.DEFAULT_TARGETS if get_path(tgt) in self.built ] # If we found an overlap between SCons's list of default # targets and the targets we created ninja builds for then use # those as ninja's default as well. if scons_default_targets: ninja.default(" ".join(scons_default_targets)) with open(ninja_file, "w") as build_ninja: build_ninja.write(content.getvalue()) self.__generated = True def get_path(node): """ Return a fake path if necessary. As an example Aliases use this as their target name in Ninja. """ if hasattr(node, "get_path"): return node.get_path() return str(node) def rfile(node): """ Return the repository file for node if it has one. Otherwise return node """ if hasattr(node, "rfile"): return node.rfile() return node def src_file(node): """Returns the src code file if it exists.""" if hasattr(node, "srcnode"): src = node.srcnode() if src.stat() is not None: return src return get_path(node) def get_comstr(env, action, targets, sources): """Get the un-substituted string for action.""" # Despite being having "list" in it's name this member is not # actually a list. It's the pre-subst'd string of the command. We # use it to determine if the command we're about to generate needs # to use a custom Ninja rule. By default this redirects CC, CXX, # AR, SHLINK, and LINK commands to their respective rules but the # user can inject custom Ninja rules and tie them to commands by # using their pre-subst'd string. if hasattr(action, "process"): return action.cmd_list return action.genstring(targets, sources, env) def get_command_env(env): """ Return a string that sets the enrivonment for any environment variables that differ between the OS environment and the SCons command ENV. It will be compatible with the default shell of the operating system. """ try: return env["NINJA_ENV_VAR_CACHE"] except KeyError: pass # Scan the ENV looking for any keys which do not exist in # os.environ or differ from it. We assume if it's a new or # differing key from the process environment then it's # important to pass down to commands in the Ninja file. ENV = get_default_ENV(env) scons_specified_env = { key: value for key, value in ENV.items() if key not in os.environ or os.environ.get(key, None) != value } windows = env["PLATFORM"] == "win32" command_env = "" for key, value in scons_specified_env.items(): # Ensure that the ENV values are all strings: if is_List(value): # If the value is a list, then we assume it is a # path list, because that's a pretty common list-like # value to stick in an environment variable: value = flatten_sequence(value) value = joinpath(map(str, value)) else: # If it isn't a string or a list, then we just coerce # it to a string, which is the proper way to handle # Dir and File instances and will produce something # reasonable for just about everything else: value = str(value) if windows: command_env += "set '{}={}' && ".format(key, value) else: command_env += "{}={} ".format(key, value) env["NINJA_ENV_VAR_CACHE"] = command_env return command_env def gen_get_response_file_command(env, rule, tool, tool_is_dynamic=False): """Generate a response file command provider for rule name.""" # If win32 using the environment with a response file command will cause # ninja to fail to create the response file. Additionally since these rules # generally are not piping through cmd.exe /c any environment variables will # make CreateProcess fail to start. # # On POSIX we can still set environment variables even for compile # commands so we do so. use_command_env = not env["PLATFORM"] == "win32" if "$" in tool: tool_is_dynamic = True def get_response_file_command(env, node, action, targets, sources, executor=None): if hasattr(action, "process"): cmd_list, _, _ = action.process(targets, sources, env, executor=executor) cmd_list = [str(c).replace("$", "$$") for c in cmd_list[0]] else: command = generate_command( env, node, action, targets, sources, executor=executor ) cmd_list = shlex.split(command) if tool_is_dynamic: tool_command = env.subst( tool, target=targets, source=sources, executor=executor ) else: tool_command = tool try: # Add 1 so we always keep the actual tool inside of cmd tool_idx = cmd_list.index(tool_command) + 1 except ValueError: raise Exception( "Could not find tool {} in {} generated from {}".format( tool, cmd_list, get_comstr(env, action, targets, sources) ) ) cmd, rsp_content = cmd_list[:tool_idx], cmd_list[tool_idx:] rsp_content = " ".join(rsp_content) variables = {"rspc": rsp_content} variables[rule] = cmd if use_command_env: variables["env"] = get_command_env(env) return rule, variables return get_response_file_command def generate_command(env, node, action, targets, sources, executor=None): # Actions like CommandAction have a method called process that is # used by SCons to generate the cmd_line they need to run. So # check if it's a thing like CommandAction and call it if we can. if hasattr(action, "process"): cmd_list, _, _ = action.process(targets, sources, env, executor=executor) cmd = _string_from_cmd_list(cmd_list[0]) else: # Anything else works with genstring, this is most commonly hit by # ListActions which essentially call process on all of their # commands and concatenate it for us. genstring = action.genstring(targets, sources, env) if executor is not None: cmd = env.subst(genstring, executor=executor) else: cmd = env.subst(genstring, targets, sources) cmd = cmd.replace("\n", " && ").strip() if cmd.endswith("&&"): cmd = cmd[0:-2].strip() # Escape dollars as necessary return cmd.replace("$", "$$") def get_shell_command(env, node, action, targets, sources, executor=None): return ( "CMD", { "cmd": generate_command(env, node, action, targets, sources, executor=None), "env": get_command_env(env), }, ) def get_command(env, node, action): # pylint: disable=too-many-branches """Get the command to execute for node.""" if node.env: sub_env = node.env else: sub_env = env executor = node.get_executor() if executor is not None: tlist = executor.get_all_targets() slist = executor.get_all_sources() else: if hasattr(node, "target_peers"): tlist = node.target_peers else: tlist = [node] slist = node.sources # Retrieve the repository file for all sources slist = [rfile(s) for s in slist] # Generate a real CommandAction if isinstance(action, SCons.Action.CommandGeneratorAction): # pylint: disable=protected-access action = action._generate(tlist, slist, sub_env, 1, executor=executor) variables = {} comstr = get_comstr(sub_env, action, tlist, slist) if not comstr: return None provider = __NINJA_RULE_MAPPING.get(comstr, get_shell_command) rule, variables = provider(sub_env, node, action, tlist, slist, executor=executor) # Get the dependencies for all targets implicit = list({dep for tgt in tlist for dep in get_dependencies(tgt)}) ninja_build = { "order_only": get_order_only(node), "outputs": get_outputs(node), "inputs": get_inputs(node), "implicit": implicit, "rule": rule, "variables": variables, } # Don't use sub_env here because we require that NINJA_POOL be set # on a per-builder call basis to prevent accidental strange # behavior like env['NINJA_POOL'] = 'console' and sub_env can be # the global Environment object if node.env is None. # Example: # # Allowed: # # env.Command("ls", NINJA_POOL="ls_pool") # # Not allowed and ignored: # # env["NINJA_POOL"] = "ls_pool" # env.Command("ls") # if node.env and node.env.get("NINJA_POOL", None) is not None: ninja_build["pool"] = node.env["NINJA_POOL"] return ninja_build def ninja_builder(env, target, source): """Generate a build.ninja for source.""" if not isinstance(source, list): source = [source] if not isinstance(target, list): target = [target] # We have no COMSTR equivalent so print that we're generating # here. print("Generating:", str(target[0])) generated_build_ninja = target[0].get_abspath() NINJA_STATE.generate(generated_build_ninja) return 0 # pylint: disable=too-few-public-methods class AlwaysExecAction(SCons.Action.FunctionAction): """Override FunctionAction.__call__ to always execute.""" def __call__(self, *args, **kwargs): kwargs["execute"] = 1 return super().__call__(*args, **kwargs) def register_custom_handler(env, name, handler): """Register a custom handler for SCons function actions.""" env[NINJA_CUSTOM_HANDLERS][name] = handler def register_custom_rule_mapping(env, pre_subst_string, rule): """Register a custom handler for SCons function actions.""" global __NINJA_RULE_MAPPING __NINJA_RULE_MAPPING[pre_subst_string] = rule def register_custom_rule(env, rule, command, description="", deps=None, pool=None): """Allows specification of Ninja rules from inside SCons files.""" rule_obj = { "command": command, "description": description if description else "{} $out".format(rule), } if deps is not None: rule_obj["deps"] = deps if pool is not None: rule_obj["pool"] = pool env[NINJA_RULES][rule] = rule_obj def register_custom_pool(env, pool, size): """Allows the creation of custom Ninja pools""" env[NINJA_POOLS][pool] = size def ninja_csig(original): """Return a dummy csig""" def wrapper(self): name = str(self) if "SConscript" in name or "SConstruct" in name: return original(self) return "dummy_ninja_csig" return wrapper def ninja_contents(original): """Return a dummy content without doing IO""" def wrapper(self): name = str(self) if "SConscript" in name or "SConstruct" in name: return original(self) return bytes("dummy_ninja_contents", encoding="utf-8") return wrapper def ninja_stat(_self, path): """ Eternally memoized stat call. SCons is very aggressive about clearing out cached values. For our purposes everything should only ever call stat once since we're running in a no_exec build the file system state should not change. For these reasons we patch SCons.Node.FS.LocalFS.stat to use our eternal memoized dictionary. """ global NINJA_STAT_MEMO try: return NINJA_STAT_MEMO[path] except KeyError: try: result = os.stat(path) except os.error: result = None NINJA_STAT_MEMO[path] = result return result def ninja_noop(*_args, **_kwargs): """ A general purpose no-op function. There are many things that happen in SCons that we don't need and also don't return anything. We use this to disable those functions instead of creating multiple definitions of the same thing. """ return None def ninja_whereis(thing, *_args, **_kwargs): """Replace env.WhereIs with a much faster version""" global NINJA_WHEREIS_MEMO # Optimize for success, this gets called significantly more often # when the value is already memoized than when it's not. try: return NINJA_WHEREIS_MEMO[thing] except KeyError: # We do not honor any env['ENV'] or env[*] variables in the # generated ninja ile. Ninja passes your raw shell environment # down to it's subprocess so the only sane option is to do the # same during generation. At some point, if and when we try to # upstream this, I'm sure a sticking point will be respecting # env['ENV'] variables and such but it's actually quite # complicated. I have a naive version but making it always work # with shell quoting is nigh impossible. So I've decided to # cross that bridge when it's absolutely required. path = shutil.which(thing) NINJA_WHEREIS_MEMO[thing] = path return path def ninja_always_serial(self, num, taskmaster): """Replacement for SCons.Job.Jobs constructor which always uses the Serial Job class.""" # We still set self.num_jobs to num even though it's a lie. The # only consumer of this attribute is the Parallel Job class AND # the Main.py function which instantiates a Jobs class. It checks # if Jobs.num_jobs is equal to options.num_jobs, so if the user # provides -j12 but we set self.num_jobs = 1 they get an incorrect # warning about this version of Python not supporting parallel # builds. So here we lie so the Main.py will not give a false # warning to users. self.num_jobs = num self.job = SCons.Job.Serial(taskmaster) class NinjaNoResponseFiles(SCons.Platform.TempFileMunge): """Overwrite the __call__ method of SCons' TempFileMunge to not delete.""" def __call__(self, target, source, env, for_signature): return self.cmd def _print_cmd_str(*_args, **_kwargs): """Disable this method""" pass def exists(env): """Enable if called.""" # This variable disables the tool when storing the SCons command in the # generated ninja file to ensure that the ninja tool is not loaded when # SCons should do actual work as a subprocess of a ninja build. The ninja # tool is very invasive into the internals of SCons and so should never be # enabled when SCons needs to build a target. if env.get("__NINJA_NO", "0") == "1": return False return True def generate(env): """Generate the NINJA builders.""" env[NINJA_SYNTAX] = env.get(NINJA_SYNTAX, "ninja_syntax.py") # Add the Ninja builder. always_exec_ninja_action = AlwaysExecAction(ninja_builder, {}) ninja_builder_obj = SCons.Builder.Builder(action=always_exec_ninja_action) env.Append(BUILDERS={"Ninja": ninja_builder_obj}) env["NINJA_PREFIX"] = env.get("NINJA_PREFIX", "build") env["NINJA_SUFFIX"] = env.get("NINJA_SUFFIX", "ninja") env["NINJA_ALIAS_NAME"] = env.get("NINJA_ALIAS_NAME", "generate-ninja") ninja_file_name = env.subst("${NINJA_PREFIX}.${NINJA_SUFFIX}") ninja_file = env.Ninja(target=ninja_file_name, source=[]) env.AlwaysBuild(ninja_file) env.Alias("$NINJA_ALIAS_NAME", ninja_file) # This adds the required flags such that the generated compile # commands will create depfiles as appropriate in the Ninja file. if env["PLATFORM"] == "win32": env.Append(CCFLAGS=["/showIncludes"]) else: env.Append(CCFLAGS=["-MMD", "-MF", "${TARGET}.d"]) # Provide a way for custom rule authors to easily access command # generation. env.AddMethod(get_shell_command, "NinjaGetShellCommand") env.AddMethod(gen_get_response_file_command, "NinjaGenResponseFileProvider") # Provides a way for users to handle custom FunctionActions they # want to translate to Ninja. env[NINJA_CUSTOM_HANDLERS] = {} env.AddMethod(register_custom_handler, "NinjaRegisterFunctionHandler") # Provides a mechanism for inject custom Ninja rules which can # then be mapped using NinjaRuleMapping. env[NINJA_RULES] = {} env.AddMethod(register_custom_rule, "NinjaRule") # Provides a mechanism for inject custom Ninja pools which can # be used by providing the NINJA_POOL="name" as an # OverrideEnvironment variable in a builder call. env[NINJA_POOLS] = {} env.AddMethod(register_custom_pool, "NinjaPool") # Add the ability to register custom NinjaRuleMappings for Command # builders. We don't store this dictionary in the env to prevent # accidental deletion of the CC/XXCOM mappings. You can still # overwrite them if you really want to but you have to explicit # about it this way. The reason is that if they were accidentally # deleted you would get a very subtly incorrect Ninja file and # might not catch it. env.AddMethod(register_custom_rule_mapping, "NinjaRuleMapping") # TODO: change LINKCOM and SHLINKCOM to handle embedding manifest exe checks # without relying on the SCons hacks that SCons uses by default. if env["PLATFORM"] == "win32": from SCons.Tool.mslink import compositeLinkAction if env["LINKCOM"] == compositeLinkAction: env[ "LINKCOM" ] = '${TEMPFILE("$LINK $LINKFLAGS /OUT:$TARGET.windows $_LIBDIRFLAGS $_LIBFLAGS $_PDB $SOURCES.windows", "$LINKCOMSTR")}' env[ "SHLINKCOM" ] = '${TEMPFILE("$SHLINK $SHLINKFLAGS $_SHLINK_TARGETS $_LIBDIRFLAGS $_LIBFLAGS $_PDB $_SHLINK_SOURCES", "$SHLINKCOMSTR")}' # Normally in SCons actions for the Program and *Library builders # will return "${*COM}" as their pre-subst'd command line. However # if a user in a SConscript overwrites those values via key access # like env["LINKCOM"] = "$( $ICERUN $)" + env["LINKCOM"] then # those actions no longer return the "bracketted" string and # instead return something that looks more expanded. So to # continue working even if a user has done this we map both the # "bracketted" and semi-expanded versions. def robust_rule_mapping(var, rule, tool): provider = gen_get_response_file_command(env, rule, tool) env.NinjaRuleMapping("${" + var + "}", provider) env.NinjaRuleMapping(env[var], provider) robust_rule_mapping("CCCOM", "CC", env["CC"]) robust_rule_mapping("SHCCCOM", "CC", env["CC"]) robust_rule_mapping("CXXCOM", "CXX", env["CXX"]) robust_rule_mapping("SHCXXCOM", "CXX", env["CXX"]) robust_rule_mapping("LINKCOM", "LINK", "$LINK") robust_rule_mapping("SHLINKCOM", "LINK", "$SHLINK") robust_rule_mapping("ARCOM", "AR", env["AR"]) # Make SCons node walk faster by preventing unnecessary work env.Decider("timestamp-match") # Used to determine if a build generates a source file. Ninja # requires that all generated sources are added as order_only # dependencies to any builds that *might* use them. env["NINJA_GENERATED_SOURCE_SUFFIXES"] = [".h", ".hpp"] if env["PLATFORM"] != "win32" and env.get("RANLIBCOM"): # There is no way to translate the ranlib list action into # Ninja so add the s flag and disable ranlib. # # This is equivalent to Meson. # https://github.com/mesonbuild/meson/blob/master/mesonbuild/linkers.py#L143 old_arflags = str(env["ARFLAGS"]) if "s" not in old_arflags: old_arflags += "s" env["ARFLAGS"] = SCons.Util.CLVar([old_arflags]) # Disable running ranlib, since we added 's' above env["RANLIBCOM"] = "" # This is the point of no return, anything after this comment # makes changes to SCons that are irreversible and incompatible # with a normal SCons build. We return early if __NINJA_NO=1 has # been given on the command line (i.e. by us in the generated # ninja file) here to prevent these modifications from happening # when we want SCons to do work. Everything before this was # necessary to setup the builder and other functions so that the # tool can be unconditionally used in the users's SCons files. if not exists(env): return # Set a known variable that other tools can query so they can # behave correctly during ninja generation. env["GENERATING_NINJA"] = True # These methods are no-op'd because they do not work during ninja # generation, expected to do no work, or simply fail. All of which # are slow in SCons. So we overwrite them with no logic. SCons.Node.FS.File.make_ready = ninja_noop SCons.Node.FS.File.prepare = ninja_noop SCons.Node.FS.File.push_to_cache = ninja_noop SCons.Executor.Executor.prepare = ninja_noop SCons.Taskmaster.Task.prepare = ninja_noop SCons.Node.FS.File.built = ninja_noop SCons.Node.Node.visited = ninja_noop # We make lstat a no-op because it is only used for SONAME # symlinks which we're not producing. SCons.Node.FS.LocalFS.lstat = ninja_noop # This is a slow method that isn't memoized. We make it a noop # since during our generation we will never use the results of # this or change the results. SCons.Node.FS.is_up_to_date = ninja_noop # We overwrite stat and WhereIs with eternally memoized # implementations. See the docstring of ninja_stat and # ninja_whereis for detailed explanations. SCons.Node.FS.LocalFS.stat = ninja_stat SCons.Util.WhereIs = ninja_whereis # Monkey patch get_csig and get_contents for some classes. It # slows down the build significantly and we don't need contents or # content signatures calculated when generating a ninja file since # we're not doing any SCons caching or building. SCons.Executor.Executor.get_contents = ninja_contents( SCons.Executor.Executor.get_contents ) SCons.Node.Alias.Alias.get_contents = ninja_contents( SCons.Node.Alias.Alias.get_contents ) SCons.Node.FS.File.get_contents = ninja_contents(SCons.Node.FS.File.get_contents) SCons.Node.FS.File.get_csig = ninja_csig(SCons.Node.FS.File.get_csig) SCons.Node.FS.Dir.get_csig = ninja_csig(SCons.Node.FS.Dir.get_csig) SCons.Node.Alias.Alias.get_csig = ninja_csig(SCons.Node.Alias.Alias.get_csig) # Replace false action messages with nothing. env["PRINT_CMD_LINE_FUNC"] = ninja_noop # This reduces unnecessary subst_list calls to add the compiler to # the implicit dependencies of targets. Since we encode full paths # in our generated commands we do not need these slow subst calls # as executing the command will fail if the file is not found # where we expect it. env["IMPLICIT_COMMAND_DEPENDENCIES"] = False # This makes SCons more aggressively cache MD5 signatures in the # SConsign file. env.SetOption("max_drift", 1) # The Serial job class is SIGNIFICANTLY (almost twice as) faster # than the Parallel job class for generating Ninja files. So we # monkey the Jobs constructor to only use the Serial Job class. SCons.Job.Jobs.__init__ = ninja_always_serial # The environment variable NINJA_SYNTAX points to the # ninja_syntax.py module from the ninja sources found here: # https://github.com/ninja-build/ninja/blob/master/misc/ninja_syntax.py # # This should be vendored into the build sources and it's location # set in NINJA_SYNTAX. This code block loads the location from # that variable, gets the absolute path to the vendored file, gets # it's parent directory then uses importlib to import the module # dynamically. ninja_syntax_file = env[NINJA_SYNTAX] if isinstance(ninja_syntax_file, str): ninja_syntax_file = env.File(ninja_syntax_file).get_abspath() ninja_syntax_mod_dir = os.path.dirname(ninja_syntax_file) sys.path.append(ninja_syntax_mod_dir) ninja_syntax_mod_name = os.path.basename(ninja_syntax_file) ninja_syntax = importlib.import_module(ninja_syntax_mod_name.replace(".py", "")) global NINJA_STATE NINJA_STATE = NinjaState(env, ninja_syntax.Writer) # Here we will force every builder to use an emitter which makes the ninja # file depend on it's target. This forces the ninja file to the bottom of # the DAG which is required so that we walk every target, and therefore add # it to the global NINJA_STATE, before we try to write the ninja file. def ninja_file_depends_on_all(target, source, env): env.Depends(ninja_file, target) return target, source # The "Alias Builder" isn't in the BUILDERS map so we have to # modify it directly. SCons.Environment.AliasBuilder.emitter = ninja_file_depends_on_all for _, builder in env["BUILDERS"].items(): try: emitter = builder.emitter if emitter is not None: builder.emitter = SCons.Builder.ListEmitter( [emitter, ninja_file_depends_on_all] ) else: builder.emitter = ninja_file_depends_on_all # Users can inject whatever they want into the BUILDERS # dictionary so if the thing doesn't have an emitter we'll # just ignore it. except AttributeError: pass # Here we monkey patch the Task.execute method to not do a bunch of # unnecessary work. If a build is a regular builder (i.e not a conftest and # not our own Ninja builder) then we add it to the NINJA_STATE. Otherwise we # build it like normal. This skips all of the caching work that this method # would normally do since we aren't pulling any of these targets from the # cache. # # In the future we may be able to use this to actually cache the build.ninja # file once we have the upstream support for referencing SConscripts as File # nodes. def ninja_execute(self): global NINJA_STATE target = self.targets[0] target_name = str(target) if target_name != ninja_file_name and "conftest" not in target_name: NINJA_STATE.add_build(target) else: target.build() SCons.Taskmaster.Task.execute = ninja_execute # Make needs_execute always return true instead of determining out of # date-ness. SCons.Script.Main.BuildTask.needs_execute = lambda x: True # We will eventually need to overwrite TempFileMunge to make it # handle persistent tempfiles or get an upstreamed change to add # some configurability to it's behavior in regards to tempfiles. # # Set all three environment variables that Python's # tempfile.mkstemp looks at as it behaves differently on different # platforms and versions of Python. os.environ["TMPDIR"] = env.Dir("$BUILD_DIR/response_files").get_abspath() os.environ["TEMP"] = os.environ["TMPDIR"] os.environ["TMP"] = os.environ["TMPDIR"] if not os.path.isdir(os.environ["TMPDIR"]): env.Execute(SCons.Defaults.Mkdir(os.environ["TMPDIR"])) env["TEMPFILE"] = NinjaNoResponseFiles